JP2005047141A - Solution film forming method and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solution film forming method constituted so as to prevent the foaming of a solvent in a cast film, and an apparatus therefor. <P>SOLUTION: In casting equipment 16, the dope 12 is cast on a rotationally moving band 31 to form the cast film 35 to transfer the same to a drying area 40b. Air shielding plates 53 and 55 for laterally partitioning the cast film 35 into a central area A1 and side edge areas A2 are provided on the drying area 40b and hot air is blown against the central area A1 while circulated between a hot air blowing port 51a and a hot air exhaust port 51b by a hot air circulating device 51. Cooling air blowers 57 and 59 are provided on the side edge areas A2 to blow cooling air against the side edge areas A2 from a cooling air blowing port 60. By this constitution, the temperature rise of the side edge parts of the cast film 35 is suppressed and the temperature distribution in the lateral direction of the cast film 35 is uniformized to prevent the foaming of the solvent in the side edge parts of the cast film 35. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a solution casting method and apparatus for producing a film used as an optical application.

  The solution casting method can produce a film that is superior in optical isotropy and thickness uniformity compared to the melt extrusion method. In addition, since it can be precisely filtered, there is less foreign matter contamination. It is widely used in the production of films for optical applications such as film for organic EL, film for organic EL, film for polarizing plate, film for photographic photosensitive material.

  In this method, a polymer material is dissolved with a solvent to form a dope, and then the dope is cast from a die onto a support such as a rotating metal band or drum to form a cast film. And it is made to dry by blowing hot air on the casting film on a metal support body, and it peels in a place with self-supporting property, and a strip | belt-shaped film is obtained.

  However, the width of the metal support is formed wider than the width of the casting film, and if hot air is blown to the casting film cast on the metal support, the hot air is cast into the casting film. As well as drying, the metal support is also heated. For this reason, the temperature of the side edge portion of the cast film rises from the center portion, and the temperature distribution becomes nonuniform in the width direction of the cast film.

  And when hot air that satisfies the conditions necessary to give sufficient self-supporting property to the central part of the casting film is blown, the temperature becomes too high at the side edge of the casting film, and in the casting film The problem that a solvent foams will generate | occur | produce. The foamed part generates a peeling residue when the cast film is peeled off from the metal support, and if the foaming is left as it is, the peeling residue expands and eventually it becomes impossible to cast. .

  The phenomenon that the solvent is foamed is more likely to occur as the temperature of hot air to be blown becomes higher and as the content of the solvent becomes higher. Further, even when the casting width is wide, the temperature difference between the central portion and the side edge portion becomes large, and both side portions are easily foamed. For this reason, if the temperature of the hot air to be blown is lowered, problems due to the foaming of the solvent can be avoided, but if this is done, it will take time until the center of the casting film has self-supporting properties. The casting speed is lowered and productivity is lowered. Although a method of avoiding problems by changing the dope formulation can be considered, even if the occurrence of foaming is reduced in this way, the optical performance of the film may be deteriorated, which is not a good measure.

For this reason, in patent document 1, a wind-shielding board is provided in the both ends of a casting film so that a hot air may not hit a metal support body, and the malfunction that a solvent foams in the side edge part of a casting film is prevented. A method for producing such a film is described.
JP 61-110520 A

  However, the method described in the above publication does not sufficiently consider the arrangement position of the wind shielding plate. For this reason, when the windshield is located near the side edge of the casting film or when the gap between the windshield and the casting film is too large, the hot air leaking from the windshield is supported by the metal. It heats up the body.

  Furthermore, in recent years, due to market demands, it has been required to increase the production speed and to reduce the film thickness. However, in order to increase the speed, the temperature of hot air blown to the casting film on the support must be increased. Therefore, the temperature at the side edge of the casting film rises and foams more easily, and as the film becomes thinner, it becomes more susceptible to the temperature of the support, so the conventional method is insufficient as a countermeasure against foaming. .

  In order to solve the above problems, the solution casting method of the present invention is provided with a wind-shielding member so as to partition a cast film on a support into a central area and a side edge area in the width direction, and the central area Hot air is blown to make the temperature distribution in the width direction of the cast film uniform. Cold air may be blown to the side edge area from the inner side to the outer side in the width direction of the casting film on the support to make the temperature distribution in the width direction of the casting film uniform.

  The solution casting method of the present invention is characterized in that cold air is blown from the inner side to the outer side in the width direction of the casting film on the support to uniform the temperature distribution in the width direction of the casting film. .

  The wind-shielding member may be provided in parallel to the side edge within a range of 20 mm to 100 mm, more preferably 20 mm to 80 mm, from the side edge of the cast film to the center side. In addition, the gap between the wind-shielding member and the cast film may be 5 mm to 30 mm, more preferably 5 mm to 15 mm.

  The cool air blow is performed by a blow duct, and a blow opening of the blow duct is provided in parallel with the side edge within a range of 20 mm to 100 mm from the side edge of the casting film to the center side, and the blow opening and the casting film. The gap is set to 5 mm to 30 mm, and the cold air is blown so as to have an intersection angle of 45 degrees or more and 90 degrees or less, more preferably 60 degrees or more and 80 degrees or less with respect to the casting film. Moreover, it is preferable that the cold air has a dew point of −2 ° C. or lower, a temperature of 15 ° C. or higher and 60 ° C. or lower, and blows the cold air in a range of wind speeds of 1 m / sec or higher and 10 m / sec or lower.

  It is preferable that the temperature distribution in the width direction of the cast film is made uniform when the solvent content of the cast film is in the range of 30% or more and 85% or less in terms of wet weight basis weight%. Moreover, it is preferable that the moving speed of the said support body is 45 m / min or more and 100 m / min or less. Furthermore, it is preferable that the film is a cellulose ester film, the film thickness on the support is from 100 μm to 750 μm, more preferably from 100 μm to 300 μm, and the width is from 800 mm to 2200 mm.

  Moreover, the solution casting apparatus of the present invention includes the hot air blowing means for blowing the hot air to the central portion in the width direction of the casting film on the support, and the casting film on the support includes the central portion. A windshield member is provided that partitions into a central area and a side edge area, suppresses the flow of the hot air to the outside in the width direction of the casting film, and equalizes the temperature distribution in the width direction of the casting film. Yes. The side edge area may be provided with a cold air blowing means that blows cold air from the inner side to the outer side in the width direction of the casting film on the support to make the temperature distribution in the width direction of the casting film uniform. .

  Furthermore, the solution casting apparatus of the present invention is provided with a cold air blowing means for blowing cold air from the inner side to the outer side in the width direction of the casting film on the support to make the temperature distribution in the width direction of the casting film uniform. It is characterized by providing.

  The solution casting method and apparatus of the present invention regulates the blowing of hot air to the side edge of the casting film by the wind shielding member, thereby making the temperature distribution in the width direction of the casting film uniform, There is an advantage that foaming of the solvent in the part can be prevented. Further, by actively cooling the side edge portion of the casting film by the cold air blowing means, there is an advantage that the temperature distribution in the width direction of the casting film can be made uniform and the foaming of the solvent at the side edge portion can be prevented. is there.

  The polymer for the raw material used in the present invention is not particularly limited as long as it is various polymer materials that can be formed by a solution casting method. Preferred is a cellulose ester used for optoelectronic applications such as a polarizing plate protective film, and particularly preferred is cellulose triacetate.

  In the present invention, the film can be produced from a dope using various known solvents. When cellulose triacetate is used as a raw material polymer material for the film, a halogenated hydrocarbon such as methylene chloride, an alcohol such as methanol, an ester, an ether, or the like can be used alone or in combination. The solvent content may be appropriately adjusted, and the present invention is not limited thereby. However, the solvent content is preferably 30% by weight to 85% by weight based on the wet weight.

  In general, the dissolved dope removes foreign matters and undissolved raw materials by filtration. For filtration, various known filter media such as filter paper, filter cloth, non-woven fabric, metal mesh, sintered metal filter, and perforated plate can be used. By filtering, foreign matters, undissolved substances, etc. in the dope can be removed, and the deterioration, damage, and defects of product performance due to these can be reduced or removed.

  In addition, the dope once dissolved can be heated to further improve the solubility. For heating, there are a method of heating while stirring in a stationary tank, a method of heating while transferring the dope using various heat exchangers such as a multi-tube type, jacket pipe with a static mixer, and the like. Moreover, it is also possible to heat to the temperature more than the boiling point of dope by providing a cooling process after a heating process, and pressurizing the inside of an apparatus. By performing these heat treatments, the fine undissolved material that could not be completely dissolved can be dissolved to a level that can be completely or practically ignored. Can be reduced.

  It is possible to add a known additive to the dope in the present invention. Examples of the additive include, but are not limited to, an ultraviolet absorber, a dispersant, a plasticizer, and a matting agent. In addition, silica, kaolin, talc, methylene chloride, methanol, or the like can be added to the dope as other additives. These additives can be mixed at the same time when the dope is prepared, or can be mixed in-line using a static mixer or the like when the dope is prepared and then transferred.

  FIG. 1 shows a solution casting line embodying the present invention. The dope prepared as described above is cast to produce a film. The solution casting line has a casting equipment 16, a drying equipment 17, and a winding equipment 18 as its basic configuration. A dope preparation facility may be provided before the casting facility, and the dope may be prepared in the solution film production line.

  The casting facility 16 is provided with a drying casing 40 including a casting area 40a, a drying area 40b, and a stripping area 40c, a hot air circulator 51, and the like. As will be described in detail later, in the casting facility 16, the dope 12 is cast from the casting die 14 onto the band 31 to form a belt-shaped casting film 35. The casting film 35 is blown by hot air by the hot air circulator 51 in the drying area 40b in the drying casing 40, and after the solvent is gradually volatilized so as to have self-supporting property, The film is peeled off from the band 31 and a film 36 is generated.

  The film thickness, width, and casting speed of the casting film 35 on the band 31 can be appropriately changed. When the film thickness is H, the width is W, and the casting speed Vf, 100 μm ≦ H It is preferable to satisfy ≦ 750 μm, 800 mm ≦ W ≦ 2200 mm, 45 m / min ≦ Vf ≦ 100 m / min. Particularly preferably, the film thickness H satisfies 100 μm ≦ H ≦ 300 μm. In this embodiment, a single-layer cast film is formed using one kind of dope. However, the present invention is also applied to the case of forming a multilayer film having two or more layers. The

  The peeling roller 37 may be a free roller or a driving roller. When driven, the peeling roller 37 is based on at least one control amount among the draw ratio, tension, and sag of the film 36. Preferably it is driven. Here, it is assumed that the peeling roller 37 has both functions of peeling off the film 36 and guiding it to the drying equipment 17, but the peeling roller for peeling off the film 36 and the film A guide roller (not shown) that guides 36 to the drying equipment 17 may be provided separately in the solution casting line.

  The drying facility 17 includes a tenter device 41 and a roller drying device 42. In the tenter device 41, the film 36 is dried while its side edges are held and tension is applied. Thereafter, the film 36 is further dried by a roller drying device 42 provided with a large number of rollers 43. After drying, the film 36 passes through a cooler (not shown) attached to the roller drying device 42. It is preferable to be cooled to room temperature.

  The film 36 that has been subjected to a sufficient drying process is preferably trimmed so that the product width is obtained by the trimming device 46, and thereafter wound by a winder 47. In the present invention, a roller 48 for conveyance is appropriately installed between the facilities and between the apparatuses to convey the film 36, and the number of the installation is not limited. Further, the present invention does not depend on the configuration and method of the drying equipment 17 and the winding equipment 18 described above, and may be implemented by various known drying methods and winding methods.

  Hereinafter, the casting equipment 16 which concerns on this invention is demonstrated in detail using FIG. 2, FIG. FIG. 2 is a schematic view showing the main part of the casting equipment 16, and is a perspective view observed from above. FIG. 3 is a cross-sectional view in the a-a ′ direction in FIG. 2.

  The casting facility 16 includes a casting die 14, a band 31, and a drying casing 40. The dope 12 is supplied to the casting die 14 and cast on a band 31 which is a support. The band 31 is made of stainless steel, for example, and is stretched horizontally between the two drums 32 and 33. The band 31 is rotated by the drums 32 and 33 being driven to rotate.

  The dope 12 from the casting die 14 becomes a belt-like casting film 35 on the band 31 and moves as the band 31 rotates. A drying casing 40 is provided so as to cover the band 31 and the casting film 35 along the movement path of the casting film 35. The drying casing 40 includes a casting area 40a where the casting die 14 is disposed, a drying area 40b for drying the casting film 35 as the band 31 rotates, and a casting film 35 having self-supporting property by drying. The film 36 is divided into a peeling area 40c to be peeled off. A chamber (not shown) is provided on the upstream side in the moving direction of the band 31 with respect to the casting die 14 in the casting area 40a as necessary, so that the dope 12 can always flow on the band 31 in a stable shape. It is extended.

  In the drying area 40b, wind shielding plates 53 and 55, a hot air blowing port 51a, a hot air discharging port 51b and a cold air blowing device 57 and 59 constituting the hot air circulator 51 are provided. The wind shielding plates 53 and 55 are respectively arranged on the inner side of the side edge of the casting film 35 so as to partition the casting film 35 on the band 31 into the central area A1 and the side edge area A2 in the width direction. . The wind shielding plates 53 and 55 are formed long in the casting direction.

  The attachment position of the wind shielding plates 53 and 55 is not particularly limited. However, when the distance from the side edge of the casting film 35 to the center side is L1, the position satisfies 20 mm ≦ L1 ≦ 100 mm. It is preferable that the distance L1 satisfy 20 mm ≦ L1 ≦ 80 mm. When the wind shielding plates 53 and 55 are provided in a range where the distance L1 is 20 mm or less, the wind shielding effect of the hot air blown to the band 31 is not changed, but the wind shielding effect on the casting film 35 is reduced, and foaming occurs. It tends to happen. In addition, if the wind shielding plates 53 and 55 are provided in a range where the distance L1 is 100 mm or more, drying of the portions other than the side edge portions of the casting film 35 is delayed, and there is a possibility that the remaining peeling occurs.

  Further, the wind shielding plates 53 and 55 are preferably provided at a position satisfying 5 mm ≦ G1 ≦ 30 mm when the gap between the windshield film 35 and G1 is G1, and it is particularly preferable to satisfy 5 mm ≦ G1 ≦ 15 mm. . If the wind shielding plates 53 and 55 are provided in the range where the gap G1 is 5 mm or less, the risk of damaging the band 31 in the case of troubles during casting work is increased, which is not a good idea. Moreover, if the wind shielding plates 53 and 55 are provided in a range where the gap G1 is 30 mm or more, a large amount of hot air blown to the inside of the wind shielding plates 53 and 55 leaks to the side edge area A2, thereby providing a wind shielding effect. It is not a good idea because it will be drastically reduced. Further, the wind shielding plates 53 and 55 can be formed using an arbitrary material, but it is preferable to use SUS in consideration of the influence of rust and the like, and in particular, SUS316 or SUS316L is used. preferable.

  The hot air blowing port 51a is formed on the upstream side of the casting film 35 in the traveling direction, and blows hot air for drying the casting film 35 to the central area A1. On the other hand, the hot air exhaust port 51b is formed on the downstream side in the running direction of the casting film 35, and sucks in the surrounding air containing the solvent volatilized by the blown hot air. A hot air blowing port 51c is provided near the stripping area 40c below the band 31. The hot air blowing port 51c blows hot air toward the hot air exhaust port 51b.

  The hot air blowing ports 51a and 51c and the hot air exhaust port 51b are connected to the hot air circulator 51 (see FIG. 1), and the hot air circulator 51 condenses and recovers the solvent contained in the air sucked from the hot air exhaust port 51b. Then, the air is purified, and hot air is sent to the casting film 35 from the hot air blowing ports 51a and 51c again. As described above, the hot air circulates in the drying area 40b, whereby the solvent in the casting film 35 is volatilized, and the casting film 35 becomes self-supporting.

  The cold air blowers 57 and 59 are disposed in the side edge area A2, and the cold air blowing ports 60 are provided on the lower surfaces. The cold air blowers 57 and 59 blow cool air from the cold air blowing port 60 provided on the inner side of the side edge of the casting film 35 toward the side edge of the casting film 35, and the side edge of the casting film 35. Cool the part. Further, since the wind shielding plates 53 and 55 are respectively arranged inside the cold air blowing port 60, after the cold air is blown to the side edge of the casting film 35, the outside of the casting film 35 in the width direction. The band 31 is cooled by diffusing.

  Conditions such as the dew point, temperature, and wind speed of the cold air blown by the cold air blowers 57 and 59 can be changed as appropriate, but in order to efficiently cool the casting film 35 and the band 31, the dew point is set to DP, temperature It is preferable that DP ≦ −2 ° C., 15 ° C. ≦ T ≦ 60 ° C., 1 m / sec ≦ Vc ≦ 10 m / sec, where T is T and the wind speed is Vc. Further, the cold air blowing port 60 has a distance from the side edge of the casting film 35 to the central portion side as L2, and a gap between the casting film 35 and the cold air blowing port 60 as G2, 20 mm ≦ L2 ≦ 100 mm, It is preferable to provide at a position satisfying 5 mm ≦ G2 ≦ 30 mm. Further, it is preferable that the cool air is blown so as to satisfy 45 degrees ≦ θ ≦ 90 degrees when the crossing angle with respect to the casting film 35 is θ, in particular, 60 degrees ≦ θ ≦ 80 degrees, It is preferable to satisfy.

  The operation of the present invention having the above configuration will be described below. The dope 12 cast on the rotating band 31 in the casting facility 16 forms a casting film 35 and is transferred to the drying area 40b. And a solvent is volatilized gradually so that it may have self-supporting property in the dry area 40b.

  At this time, hot air is blown from the hot air circulator 51 to the central area A1 of the casting film 35, but wind shields 53 and 55 are disposed on both outer sides of the hot air circulator 51, and the hot air flows. Air blowing to the side edge area A2 of the casting film 35 is restricted. Further, in the side edge area A2 of the casting film 35, cold air is blown from the cold air blowers 57 and 59, and the side edge area A2 and the band 31 are cooled.

  Thereby, the temperature rise in the side edge area A2 of the casting film 35 is suppressed, the temperature distribution in the width direction of the casting film 35 is made uniform, and the problem that the solvent foams in the side edge area A2 is prevented. be able to.

  Hereinafter, specific examples of the present invention will be described based on FIGS. 4 and 5 in comparison with comparative examples. FIG. 4 is a cross-sectional view of the drying area showing the arrangement position of the wind shields and the installation state of the cold air blower. FIG. 4 (A) shows Example 1, and FIG. 4 (B) shows Comparative Example 1. (C) shows Example 2, FIG. (D) shows Comparative Example 2, and (E) shows Comparative Example 3. FIG. FIG. 5 shows specific differences in various conditions when the drying area is changed as shown in FIGS. 4 (A) to (E), the foaming state of the solvent at the side edge of the casting film, and the solvent. It is a graph which shows the evaluation result at the time of observing visually about the unstretched remaining of the cast film resulting from foaming of.

  In all the examples and comparative examples, the temperature of hot air blown by the hot air circulator was 120 ° C., the casting speed was 50 m / min, and the width of the manufactured product film was unified to 1550 mm for comparison. Further, a dope having a solvent content of 50% or more and 75% or less was used. At this time, in the drying area, the solvent content in the casting film was 75% on the upstream side in the casting direction, and the solvent content in the casting film was 40% on the downstream side in the casting direction.

  As for the foaming status of the solvent, “◎” is indicated when foaming cannot be confirmed, and “○” is indicated when partial foaming can be confirmed but it does not expand to the peeling residue. However, if the remaining part does not expand, “△” indicates that foaming is partially confirmed and if the remaining part expands, “×” indicates that foaming continuously occurs and peels off. When the rest continued, “XX” was marked in the chart for evaluation.

[Example 1]
Example 1 is an example in which only a windshield is provided in the drying area. The windshields were arranged so that L1 = 50 mm and G1 = 10 mm. When casting was performed under such conditions, foaming was confirmed at the side edge portion of the casting film, but the evaluation was evaluated as “◯” because it was at a level where it did not develop into a peeling residue.

[Comparative Example 1]
Comparative Example 1 is an example in which only the wind shielding plate is provided in the drying area, and the arrangement position of the wind shielding plate is changed with respect to Example 1. In Comparative Example 1, the wind shielding plates were arranged so that L1 = 0 mm and G1 = 30 mm. When casting was performed under such conditions, foaming was continuously confirmed at the side edge of the casting film. Furthermore, because peeling was continuously generated due to the foaming, the evaluation was “XX”.

[Example 2]
Example 2 is an example in which both a wind shielding plate and a cold air blower are provided in a drying area. The windshields were arranged so that L1 = 50 mm and G1 = 20 mm. The cold air blower was installed so that L2 = 40 mm, G2 = 20 mm, and θ = 70 °. When casting was performed under such conditions, it was possible to perform good casting without causing foaming at the side edge of the casting film, and thus the evaluation was “「 ”.

[Comparative Example 2]
The comparative example 2 is an example in which both the wind shielding plate and the cold air blower are provided in the drying area, and is an example in which the installation conditions of the wind shielding plate and the cold air blower are changed with respect to the second embodiment. In Comparative Example 2, the wind shielding plates were arranged so that L1 = 50 mm and G1 = 40 mm. The cool air blower was installed so that L2 = 40 mm, G2 = 40 mm, and θ = 70 °. When casting was performed under such conditions, foaming was confirmed at the side edge of the casting film. Furthermore, although peeling off occurred due to this foaming, the evaluation was evaluated as “Δ” because the peeling off part did not expand.

[Comparative Example 3]
Comparative Example 3 is an example in which both a wind shield and a cold air blower are provided in the drying area, as in Comparative Example 2, and the installation conditions of the wind shield and the cold air blower are changed with respect to Example 2. This is an example. In Comparative Example 3, the wind shielding plates were arranged so that L1 = 10 mm and G1 = 20 mm. The cool air blower was installed so that L2 = 0 mm, G2 = 20 mm, and θ = 90 °. When casting was performed under such conditions, foaming was confirmed at the side edge of the casting film. Further, due to the foaming, unsettled residue was generated, and the unsealable portion was enlarged, and thus the evaluation was “x”.

It is the schematic which shows a solution casting line. It is a perspective view showing casting equipment. It is sectional drawing of a drying area. It is sectional drawing of the drying area which changed the arrangement position of a windshield, and the installation condition of a cold air blower. It is a table | surface which shows the evaluation result about the difference of the various conditions at the time of changing a dry area, the foaming condition of a cast film, and a peeling residue.

Explanation of symbols

12 Dope 14 Casting die 31 Band 16 Casting equipment 35 Casting film 36 Film 40b Drying area 51 Hot air circulator 51a, 51c Hot air vent 51b Hot air vent 53, 55 Air shield 57, 59 Cold blower 60 Cold blower mouth

Claims (16)

A polymer is dissolved in a solvent to form a casting dope, and the casting dope is cast on a moving support to form a casting film, and after blowing hot air to the casting film and drying, In the solution casting method for producing a film by peeling the casting film from the support,
A solution casting method characterized by providing a wind-shielding member so as to partition a casting film on the support into a central area and a side edge area in the width direction, and blowing hot air to the central area.   The solution casting method according to claim 1, wherein cold air is blown to the side edge area from the inner side to the outer side in the width direction of the casting film on the support. A polymer is dissolved in a solvent to form a casting dope, and the casting dope is cast on a moving support to form a casting film, and after blowing hot air to the casting film and drying, In the solution casting method for producing a film by peeling the casting film from the support,
A solution casting method, wherein cold air is blown from the inner side to the outer side in the width direction of the casting film on the support.   The wind-shielding member is provided in a range from 20 mm to 100 mm from the side edge of the casting membrane to the center side, and the gap between the wind-shielding member and the casting membrane is 5 mm to 30 mm. Item 3. The solution casting method according to Item 1 or 2.   5. The solution casting method according to claim 4, wherein the wind-shielding member is provided in a range of 20 mm or more and 80 mm or less from a side edge of the cast film to a center side.   The solution casting method according to claim 4 or 5, wherein a gap between the wind-shielding member and the casting film is 5 mm or more and 15 mm or less. The cooling air is blown by a blow duct, and a blow opening of the blow duct is provided in a range from 20 mm to 100 mm from a side edge of the casting film to a central portion side, and a gap between the blow opening and the casting film is 5 mm or more. While making it below 30mm,
The solution casting method according to any one of claims 2 to 6, wherein the cold air is blown so as to have an intersection angle of 45 degrees or more and 90 degrees or less with respect to the casting film.   The solution casting method according to claim 7, wherein the cold air is blown so as to have an intersecting angle of 60 degrees or more and 80 degrees or less with respect to the casting film. The cold air has a dew point of −2 ° C. or lower, a temperature of 15 ° C. or higher and 60 ° C. or lower,
The solution casting method according to any one of claims 2 to 8, wherein the cool air is blown at a wind speed in a range of 1 m / sec to 10 m / sec.   The solution casting method according to any one of claims 1 to 9, wherein a solvent content of the cast film is 30% or more and 85% or less in terms of wet weight basis weight%.   The solution casting method according to claim 1, wherein a moving speed of the support is 45 m / min or more and 100 m / min or less.   12. The solution casting method according to claim 1, wherein the film is a cellulose ester film, the film thickness on the support is from 100 μm to 750 μm, and the width is from 800 mm to 2200 mm. .   13. The solution casting method according to claim 12, wherein the film is a cellulose ester film, and the film thickness on the support is from 100 μm to 300 μm. A polymer is dissolved in a solvent to form a casting dope, and the casting dope is cast on a moving support to form a casting film, and after blowing hot air to the casting film and drying, In the solution casting apparatus for stripping the casting film from the support to generate a film,
A hot air blowing means for blowing the hot air to the center in the width direction of the casting film on the support;
The present invention is characterized in that a casting film on the support is partitioned into a central area including the central part and a side edge area, and a wind shielding member is provided to suppress the flow of the hot air to the outside in the casting film width direction. Solution casting apparatus.   The solution casting apparatus according to claim 14, wherein cold air blowing means for blowing cold air from a width direction inner side to an outer side of the casting film on the support is provided in the side edge area. A polymer is dissolved in a solvent to form a casting dope, and the casting dope is cast on a moving support to form a casting film, and after blowing hot air to the casting film and drying, In the solution casting apparatus for stripping the casting film from the support to generate a film,
A solution casting apparatus, comprising a cold air blowing means for blowing cold air from the inner side to the outer side in the width direction of the casting film on the support.